The Mac version of DivX Player does not feature auto-update. DivX Plus (for Windows only) has auto-update.
From the link below...
"How do I configure or turn off auto-update for my DivX Plus Products?
You can manually check for updates for your DivX Plus for Windows products by:
Going to Start > Programs > DivX Plus > Check for Updates > This will launch the DivX Control Panel
You can choose to have the DivX Updater check for updates:
* Never
* Daily
* Weekly
* Monthly